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edb3359d DJ |
1 | /* Inline frame unwinder for GDB. |
2 | ||
3666a048 | 3 | Copyright (C) 2008-2021 Free Software Foundation, Inc. |
edb3359d DJ |
4 | |
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include "defs.h" | |
ddfe970e | 21 | #include "breakpoint.h" |
e451c4a1 | 22 | #include "inline-frame.h" |
edb3359d DJ |
23 | #include "addrmap.h" |
24 | #include "block.h" | |
25 | #include "frame-unwind.h" | |
26 | #include "inferior.h" | |
00431a78 | 27 | #include "gdbthread.h" |
4e485129 | 28 | #include "regcache.h" |
edb3359d | 29 | #include "symtab.h" |
51d48146 | 30 | #include "frame.h" |
b24531ed | 31 | #include <algorithm> |
edb3359d | 32 | |
edb3359d DJ |
33 | /* We need to save a few variables for every thread stopped at the |
34 | virtual call site of an inlined function. If there was always a | |
35 | "struct thread_info", we could hang it off that; in the mean time, | |
36 | keep our own list. */ | |
37 | struct inline_state | |
38 | { | |
00431a78 | 39 | inline_state (thread_info *thread_, int skipped_frames_, CORE_ADDR saved_pc_, |
7ffa82e1 | 40 | std::vector<symbol *> &&skipped_symbols_) |
00431a78 | 41 | : thread (thread_), skipped_frames (skipped_frames_), saved_pc (saved_pc_), |
7ffa82e1 | 42 | skipped_symbols (std::move (skipped_symbols_)) |
b24531ed SM |
43 | {} |
44 | ||
edb3359d | 45 | /* The thread this data relates to. It should be a currently |
00431a78 PA |
46 | stopped thread. */ |
47 | thread_info *thread; | |
edb3359d DJ |
48 | |
49 | /* The number of inlined functions we are skipping. Each of these | |
50 | functions can be stepped in to. */ | |
51 | int skipped_frames; | |
52 | ||
53 | /* Only valid if SKIPPED_FRAMES is non-zero. This is the PC used | |
54 | when calculating SKIPPED_FRAMES; used to check whether we have | |
55 | moved to a new location by user request. If so, we invalidate | |
56 | any skipped frames. */ | |
57 | CORE_ADDR saved_pc; | |
58 | ||
7ffa82e1 AB |
59 | /* Only valid if SKIPPED_FRAMES is non-zero. This is the list of all |
60 | function symbols that have been skipped, from inner most to outer | |
61 | most. It is used to find the call site of the current frame. */ | |
62 | std::vector<struct symbol *> skipped_symbols; | |
edb3359d DJ |
63 | }; |
64 | ||
b24531ed | 65 | static std::vector<inline_state> inline_states; |
edb3359d | 66 | |
00431a78 PA |
67 | /* Locate saved inlined frame state for THREAD, if it exists and is |
68 | valid. */ | |
edb3359d DJ |
69 | |
70 | static struct inline_state * | |
00431a78 | 71 | find_inline_frame_state (thread_info *thread) |
edb3359d | 72 | { |
b24531ed | 73 | auto state_it = std::find_if (inline_states.begin (), inline_states.end (), |
00431a78 | 74 | [thread] (const inline_state &state) |
b24531ed | 75 | { |
00431a78 | 76 | return state.thread == thread; |
b24531ed | 77 | }); |
edb3359d | 78 | |
b24531ed SM |
79 | if (state_it == inline_states.end ()) |
80 | return nullptr; | |
edb3359d | 81 | |
b24531ed | 82 | inline_state &state = *state_it; |
00431a78 | 83 | struct regcache *regcache = get_thread_regcache (thread); |
b24531ed | 84 | CORE_ADDR current_pc = regcache_read_pc (regcache); |
edb3359d | 85 | |
b24531ed SM |
86 | if (current_pc != state.saved_pc) |
87 | { | |
88 | /* PC has changed - this context is invalid. Use the | |
89 | default behavior. */ | |
edb3359d | 90 | |
b24531ed SM |
91 | unordered_remove (inline_states, state_it); |
92 | return nullptr; | |
93 | } | |
edb3359d | 94 | |
b24531ed | 95 | return &state; |
edb3359d DJ |
96 | } |
97 | ||
5b6d1e4f | 98 | /* See inline-frame.h. */ |
edb3359d DJ |
99 | |
100 | void | |
5b6d1e4f | 101 | clear_inline_frame_state (process_stratum_target *target, ptid_t filter_ptid) |
edb3359d | 102 | { |
5b6d1e4f | 103 | gdb_assert (target != NULL); |
edb3359d | 104 | |
5b6d1e4f | 105 | if (filter_ptid == minus_one_ptid || filter_ptid.is_pid ()) |
edb3359d | 106 | { |
5b6d1e4f PA |
107 | auto matcher = [target, &filter_ptid] (const inline_state &state) |
108 | { | |
109 | thread_info *t = state.thread; | |
110 | return (t->inf->process_target () == target | |
111 | && t->ptid.matches (filter_ptid)); | |
112 | }; | |
113 | ||
b24531ed | 114 | auto it = std::remove_if (inline_states.begin (), inline_states.end (), |
5b6d1e4f | 115 | matcher); |
b24531ed SM |
116 | |
117 | inline_states.erase (it, inline_states.end ()); | |
118 | ||
edb3359d DJ |
119 | return; |
120 | } | |
121 | ||
5b6d1e4f PA |
122 | |
123 | auto matcher = [target, &filter_ptid] (const inline_state &state) | |
124 | { | |
125 | thread_info *t = state.thread; | |
126 | return (t->inf->process_target () == target | |
127 | && filter_ptid == t->ptid); | |
128 | }; | |
129 | ||
130 | auto it = std::find_if (inline_states.begin (), inline_states.end (), | |
131 | matcher); | |
132 | ||
133 | if (it != inline_states.end ()) | |
134 | unordered_remove (inline_states, it); | |
135 | } | |
136 | ||
137 | /* See inline-frame.h. */ | |
138 | ||
139 | void | |
140 | clear_inline_frame_state (thread_info *thread) | |
141 | { | |
b24531ed | 142 | auto it = std::find_if (inline_states.begin (), inline_states.end (), |
5b6d1e4f | 143 | [thread] (const inline_state &state) |
b24531ed | 144 | { |
5b6d1e4f | 145 | return thread == state.thread; |
b24531ed SM |
146 | }); |
147 | ||
148 | if (it != inline_states.end ()) | |
149 | unordered_remove (inline_states, it); | |
edb3359d DJ |
150 | } |
151 | ||
152 | static void | |
153 | inline_frame_this_id (struct frame_info *this_frame, | |
154 | void **this_cache, | |
155 | struct frame_id *this_id) | |
156 | { | |
157 | struct symbol *func; | |
158 | ||
159 | /* In order to have a stable frame ID for a given inline function, | |
160 | we must get the stack / special addresses from the underlying | |
51d48146 PA |
161 | real frame's this_id method. So we must call |
162 | get_prev_frame_always. Because we are inlined into some | |
163 | function, there must be previous frames, so this is safe - as | |
2b3cb400 PA |
164 | long as we're careful not to create any cycles. See related |
165 | comments in get_prev_frame_always_1. */ | |
51d48146 | 166 | *this_id = get_frame_id (get_prev_frame_always (this_frame)); |
edb3359d DJ |
167 | |
168 | /* We need a valid frame ID, so we need to be based on a valid | |
169 | frame. FSF submission NOTE: this would be a good assertion to | |
170 | apply to all frames, all the time. That would fix the ambiguity | |
171 | of null_frame_id (between "no/any frame" and "the outermost | |
172 | frame"). This will take work. */ | |
173 | gdb_assert (frame_id_p (*this_id)); | |
174 | ||
175 | /* Future work NOTE: Alexandre Oliva applied a patch to GCC 4.3 | |
176 | which generates DW_AT_entry_pc for inlined functions when | |
177 | possible. If this attribute is available, we should use it | |
178 | in the frame ID (and eventually, to set breakpoints). */ | |
179 | func = get_frame_function (this_frame); | |
180 | gdb_assert (func != NULL); | |
2b1ffcfd | 181 | (*this_id).code_addr = BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (func)); |
193facb3 | 182 | (*this_id).artificial_depth++; |
edb3359d DJ |
183 | } |
184 | ||
185 | static struct value * | |
186 | inline_frame_prev_register (struct frame_info *this_frame, void **this_cache, | |
187 | int regnum) | |
188 | { | |
189 | /* Use get_frame_register_value instead of | |
190 | frame_unwind_got_register, to avoid requiring this frame's ID. | |
191 | This frame's ID depends on the previous frame's ID (unusual), and | |
192 | the previous frame's ID depends on this frame's unwound | |
193 | registers. If unwinding registers from this frame called | |
194 | get_frame_id, there would be a loop. | |
195 | ||
196 | Do not copy this code into any other unwinder! Inlined functions | |
197 | are special; other unwinders must not have a dependency on the | |
198 | previous frame's ID, and therefore can and should use | |
199 | frame_unwind_got_register instead. */ | |
200 | return get_frame_register_value (this_frame, regnum); | |
201 | } | |
202 | ||
203 | /* Check whether we are at an inlining site that does not already | |
204 | have an associated frame. */ | |
205 | ||
206 | static int | |
207 | inline_frame_sniffer (const struct frame_unwind *self, | |
208 | struct frame_info *this_frame, | |
209 | void **this_cache) | |
210 | { | |
211 | CORE_ADDR this_pc; | |
3977b71f | 212 | const struct block *frame_block, *cur_block; |
edb3359d DJ |
213 | int depth; |
214 | struct frame_info *next_frame; | |
00431a78 | 215 | struct inline_state *state = find_inline_frame_state (inferior_thread ()); |
edb3359d DJ |
216 | |
217 | this_pc = get_frame_address_in_block (this_frame); | |
218 | frame_block = block_for_pc (this_pc); | |
219 | if (frame_block == NULL) | |
220 | return 0; | |
221 | ||
222 | /* Calculate DEPTH, the number of inlined functions at this | |
223 | location. */ | |
224 | depth = 0; | |
225 | cur_block = frame_block; | |
226 | while (BLOCK_SUPERBLOCK (cur_block)) | |
227 | { | |
228 | if (block_inlined_p (cur_block)) | |
229 | depth++; | |
0fa7fe50 JB |
230 | else if (BLOCK_FUNCTION (cur_block) != NULL) |
231 | break; | |
edb3359d DJ |
232 | |
233 | cur_block = BLOCK_SUPERBLOCK (cur_block); | |
234 | } | |
235 | ||
236 | /* Check how many inlined functions already have frames. */ | |
237 | for (next_frame = get_next_frame (this_frame); | |
238 | next_frame && get_frame_type (next_frame) == INLINE_FRAME; | |
239 | next_frame = get_next_frame (next_frame)) | |
240 | { | |
241 | gdb_assert (depth > 0); | |
242 | depth--; | |
243 | } | |
244 | ||
245 | /* If this is the topmost frame, or all frames above us are inlined, | |
246 | then check whether we were requested to skip some frames (so they | |
247 | can be stepped into later). */ | |
248 | if (state != NULL && state->skipped_frames > 0 && next_frame == NULL) | |
249 | { | |
4e485129 DJ |
250 | gdb_assert (depth >= state->skipped_frames); |
251 | depth -= state->skipped_frames; | |
edb3359d DJ |
252 | } |
253 | ||
254 | /* If all the inlined functions here already have frames, then pass | |
255 | to the normal unwinder for this PC. */ | |
256 | if (depth == 0) | |
257 | return 0; | |
258 | ||
259 | /* If the next frame is an inlined function, but not the outermost, then | |
260 | we are the next outer. If it is not an inlined function, then we | |
261 | are the innermost inlined function of a different real frame. */ | |
262 | return 1; | |
263 | } | |
264 | ||
39d7b0e2 | 265 | const struct frame_unwind inline_frame_unwind = { |
edb3359d | 266 | INLINE_FRAME, |
8fbca658 | 267 | default_frame_unwind_stop_reason, |
edb3359d DJ |
268 | inline_frame_this_id, |
269 | inline_frame_prev_register, | |
270 | NULL, | |
271 | inline_frame_sniffer | |
272 | }; | |
273 | ||
edb3359d DJ |
274 | /* Return non-zero if BLOCK, an inlined function block containing PC, |
275 | has a group of contiguous instructions starting at PC (but not | |
276 | before it). */ | |
277 | ||
278 | static int | |
3977b71f | 279 | block_starting_point_at (CORE_ADDR pc, const struct block *block) |
edb3359d | 280 | { |
346d1dfe | 281 | const struct blockvector *bv; |
582942f4 | 282 | const struct block *new_block; |
edb3359d DJ |
283 | |
284 | bv = blockvector_for_pc (pc, NULL); | |
285 | if (BLOCKVECTOR_MAP (bv) == NULL) | |
286 | return 0; | |
287 | ||
582942f4 TT |
288 | new_block = (const struct block *) addrmap_find (BLOCKVECTOR_MAP (bv), |
289 | pc - 1); | |
edb3359d DJ |
290 | if (new_block == NULL) |
291 | return 1; | |
292 | ||
293 | if (new_block == block || contained_in (new_block, block)) | |
294 | return 0; | |
295 | ||
177b42fe | 296 | /* The immediately preceding address belongs to a different block, |
edb3359d DJ |
297 | which is not a child of this one. Treat this as an entrance into |
298 | BLOCK. */ | |
299 | return 1; | |
300 | } | |
301 | ||
ddfe970e | 302 | /* Loop over the stop chain and determine if execution stopped in an |
b2b38aa4 PA |
303 | inlined frame because of a breakpoint with a user-specified location |
304 | set at FRAME_BLOCK. */ | |
ddfe970e KS |
305 | |
306 | static bool | |
61b04dd0 | 307 | stopped_by_user_bp_inline_frame (const block *frame_block, bpstat stop_chain) |
ddfe970e KS |
308 | { |
309 | for (bpstat s = stop_chain; s != NULL; s = s->next) | |
310 | { | |
311 | struct breakpoint *bpt = s->breakpoint_at; | |
312 | ||
b2b38aa4 PA |
313 | if (bpt != NULL |
314 | && (user_breakpoint_p (bpt) || bpt->type == bp_until)) | |
ddfe970e | 315 | { |
b6433ede | 316 | bp_location *loc = s->bp_location_at.get (); |
ddfe970e KS |
317 | enum bp_loc_type t = loc->loc_type; |
318 | ||
991ff292 PA |
319 | if (t == bp_loc_software_breakpoint |
320 | || t == bp_loc_hardware_breakpoint) | |
321 | { | |
322 | /* If the location has a function symbol, check whether | |
323 | the frame was for that inlined function. If it has | |
324 | no function symbol, then assume it is. I.e., default | |
325 | to presenting the stop at the innermost inline | |
326 | function. */ | |
327 | if (loc->symbol == nullptr | |
328 | || frame_block == SYMBOL_BLOCK_VALUE (loc->symbol)) | |
329 | return true; | |
330 | } | |
ddfe970e KS |
331 | } |
332 | } | |
333 | ||
334 | return false; | |
335 | } | |
336 | ||
337 | /* See inline-frame.h. */ | |
edb3359d DJ |
338 | |
339 | void | |
00431a78 | 340 | skip_inline_frames (thread_info *thread, bpstat stop_chain) |
edb3359d | 341 | { |
3977b71f | 342 | const struct block *frame_block, *cur_block; |
7ffa82e1 | 343 | std::vector<struct symbol *> skipped_syms; |
edb3359d | 344 | int skip_count = 0; |
edb3359d DJ |
345 | |
346 | /* This function is called right after reinitializing the frame | |
347 | cache. We try not to do more unwinding than absolutely | |
348 | necessary, for performance. */ | |
b24531ed | 349 | CORE_ADDR this_pc = get_frame_pc (get_current_frame ()); |
edb3359d DJ |
350 | frame_block = block_for_pc (this_pc); |
351 | ||
352 | if (frame_block != NULL) | |
353 | { | |
354 | cur_block = frame_block; | |
355 | while (BLOCK_SUPERBLOCK (cur_block)) | |
356 | { | |
357 | if (block_inlined_p (cur_block)) | |
358 | { | |
359 | /* See comments in inline_frame_this_id about this use | |
2b1ffcfd KB |
360 | of BLOCK_ENTRY_PC. */ |
361 | if (BLOCK_ENTRY_PC (cur_block) == this_pc | |
edb3359d DJ |
362 | || block_starting_point_at (this_pc, cur_block)) |
363 | { | |
ddfe970e KS |
364 | /* Do not skip the inlined frame if execution |
365 | stopped in an inlined frame because of a user | |
61b04dd0 PA |
366 | breakpoint for this inline function. */ |
367 | if (stopped_by_user_bp_inline_frame (cur_block, stop_chain)) | |
368 | break; | |
369 | ||
370 | skip_count++; | |
7ffa82e1 | 371 | skipped_syms.push_back (BLOCK_FUNCTION (cur_block)); |
edb3359d DJ |
372 | } |
373 | else | |
374 | break; | |
375 | } | |
0fa7fe50 JB |
376 | else if (BLOCK_FUNCTION (cur_block) != NULL) |
377 | break; | |
378 | ||
edb3359d DJ |
379 | cur_block = BLOCK_SUPERBLOCK (cur_block); |
380 | } | |
381 | } | |
382 | ||
00431a78 | 383 | gdb_assert (find_inline_frame_state (thread) == NULL); |
7ffa82e1 AB |
384 | inline_states.emplace_back (thread, skip_count, this_pc, |
385 | std::move (skipped_syms)); | |
edb3359d DJ |
386 | |
387 | if (skip_count != 0) | |
388 | reinit_frame_cache (); | |
389 | } | |
390 | ||
391 | /* Step into an inlined function by unhiding it. */ | |
392 | ||
393 | void | |
00431a78 | 394 | step_into_inline_frame (thread_info *thread) |
edb3359d | 395 | { |
00431a78 | 396 | inline_state *state = find_inline_frame_state (thread); |
edb3359d DJ |
397 | |
398 | gdb_assert (state != NULL && state->skipped_frames > 0); | |
399 | state->skipped_frames--; | |
400 | reinit_frame_cache (); | |
401 | } | |
402 | ||
403 | /* Return the number of hidden functions inlined into the current | |
404 | frame. */ | |
405 | ||
406 | int | |
00431a78 | 407 | inline_skipped_frames (thread_info *thread) |
edb3359d | 408 | { |
00431a78 | 409 | inline_state *state = find_inline_frame_state (thread); |
edb3359d DJ |
410 | |
411 | if (state == NULL) | |
412 | return 0; | |
413 | else | |
414 | return state->skipped_frames; | |
415 | } | |
416 | ||
417 | /* If one or more inlined functions are hidden, return the symbol for | |
418 | the function inlined into the current frame. */ | |
419 | ||
420 | struct symbol * | |
00431a78 | 421 | inline_skipped_symbol (thread_info *thread) |
edb3359d | 422 | { |
00431a78 | 423 | inline_state *state = find_inline_frame_state (thread); |
edb3359d | 424 | gdb_assert (state != NULL); |
7ffa82e1 AB |
425 | |
426 | /* This should only be called when we are skipping at least one frame, | |
427 | hence SKIPPED_FRAMES will be greater than zero when we get here. | |
428 | We initialise SKIPPED_FRAMES at the same time as we build | |
429 | SKIPPED_SYMBOLS, hence it should be true that SKIPPED_FRAMES never | |
430 | indexes outside of the SKIPPED_SYMBOLS vector. */ | |
431 | gdb_assert (state->skipped_frames > 0); | |
432 | gdb_assert (state->skipped_frames <= state->skipped_symbols.size ()); | |
433 | return state->skipped_symbols[state->skipped_frames - 1]; | |
edb3359d DJ |
434 | } |
435 | ||
436 | /* Return the number of functions inlined into THIS_FRAME. Some of | |
437 | the callees may not have associated frames (see | |
438 | skip_inline_frames). */ | |
439 | ||
440 | int | |
441 | frame_inlined_callees (struct frame_info *this_frame) | |
442 | { | |
443 | struct frame_info *next_frame; | |
444 | int inline_count = 0; | |
445 | ||
446 | /* First count how many inlined functions at this PC have frames | |
447 | above FRAME (are inlined into FRAME). */ | |
448 | for (next_frame = get_next_frame (this_frame); | |
449 | next_frame && get_frame_type (next_frame) == INLINE_FRAME; | |
450 | next_frame = get_next_frame (next_frame)) | |
451 | inline_count++; | |
452 | ||
453 | /* Simulate some most-inner inlined frames which were suppressed, so | |
454 | they can be stepped into later. If we are unwinding already | |
455 | outer frames from some non-inlined frame this does not apply. */ | |
456 | if (next_frame == NULL) | |
00431a78 | 457 | inline_count += inline_skipped_frames (inferior_thread ()); |
edb3359d DJ |
458 | |
459 | return inline_count; | |
460 | } |